A Comprehensive Evaluation of Sdox, a Promising H2S-Releasing Doxorubicin for the Treatment of Chemoresistant Tumors

Sdox is a hydrogen sulfide (H2S)-releasing doxorubicin effective in P-glycoprotein-overexpressing/doxorubicin-resistant tumor models and not cytotoxic, as the parental drug, in H9c2 cardiomyocytes. The aim of this study was the assessment of Sdox drug-like features and its absorption, distribution, metabolism, and excretion (ADME)/toxicity properties, by a multi- and transdisciplinary in silico, in vitro, and in vivo approach. Doxorubicin was used as the reference compound. The in silico profiling suggested that Sdox possesses higher lipophilicity and lower solubility compared to doxorubicin, and the off-targets prediction revealed relevant differences between Dox and Sdox towards several cancer targets, suggesting different toxicological profiles. In vitro data showed that Sdox is a substrate with lower affinity for P-glycoprotein, less hepatotoxic, and causes less oxidative damage than doxorubicin. Both anthracyclines inhibited CYP3A4, but not hERG currents. Unlike doxorubicin, the percentage of zebrafish live embryos at 72 hpf was not affected by Sdox treatment. In conclusion, these findings demonstrate that Sdox displays a more favorable drug-like ADME/toxicity profile than doxorubicin, different selectivity towards cancer targets, along with a greater preclinical efficacy in resistant tumors. Therefore, Sdox represents a prototype of innovative anthracyclines, worthy of further investigations in clinical settings

Drug-drug interactions with the new oral anticoagulants

Drug-drug interactions (DDI) and adverse drug effects (ADR) have received much attention because many patients are being hospitalized or remain hospitalized longer than necessary. The use of multiple drugs (8-12 on average in hospitalized patients) is common in a number of therapeutic regimens. Anticoagulant drugs are among the most commonly implicated medications that cause ADR in hospitalized patients and medication errors involving anticoagulant drugs remain common. Elderly and cardiac patients represent populations at particularly high risk for suffering anticoagulant-associated ARD and drug interactions.We review clinically significant pharmacokinetic and pharmacodynamic drug-drug interactions (DDIs) with the new oral anticoagulants, including dabigatran, rivaroxaban, and apixaban. The main pharmacokinetic drug interactions are focused on drugs affecting the permeability glycoprotein (P-gp) efflux transporter protein and/or cytochrome P- 450 enzymes. Awareness of drugs that are involved in drug-drug interactions and especially those that alter the function of the P-gp efflux transporter protein and CYP enzymes and provide adverse effects should enable clinicians to anticipate and avoid potential DDIs involving the anticoagulants

Metabolism of 7-ethoxycoumarin by rat precision-cut liver slices

Precision cut liver slices are used in the study of drug metabolism and toxicity, The aim of the study is to investigate the metabolism of 7-ethoxycoumarin in precision cut liver slices. Liver slices were prepared from liver cores by Krumdieck tissue slicer. After 30 min preincubation period, the liver slices were incubated in RPMI1640 medium, t = 37°C, for 2h, 4h, 6h, 24h. 7-ethoxycoumarin 50 μM was added to the incubation medium. The viability of the preparation was evaluated by LDH release in both preincubation and incubation medium. The amount of free 7-hydroxycoumarin and its glucuronide and sulfate conjugates was measured spectrofluorometrically. The results of the study showed that the precision cut liver slices are an appropriate in vitro model for complex evaluation of phase I and phase II metabolism of 7-ethoxycoumarin

Neuroprotective and MAOB inhibitory effects of a series of caffeine-8-thioglycolic acid amides

The effects of new derivatives of caffeine-8-thioglycolic acid (100 μM) on isolated rat brain synaptosomes, human neuroblastoma cell line SH-SY5Y and human recombinant MAOB enzyme (hMAOB) (1 μM) were evaluated. Most of the compounds, administered alone, didn’t show statistically significant neurotoxic effects on SH-SY5Y, when compared to the control (non-treated cells). Of all studied structures JTA-2Ox, JTA-11, JTA-12 and JTA-13 decreased cell viability. In combination with 6-hydroxydopamine (6-OHDA) (100 μM), only JTA-1 and JTA-2 revealed neuroprotective effects, stronger than those of caffeine. All compounds administered alone revealed, neurotoxic effects on synaptosomes, as compared to nontreated synaptosomes. JTA-1, JTA-2 and JTA-3 showed lowest neurotoxic effects and were investigated in a model of 6-OHDA-induced oxidative stress. In this model of neurotoxicity, only JTA-1 and JTA-2 showed statistically significant neuroprotective effect, by preserving the synaptosomal viability and the level of reduced glutathione. Inhibition of hMAOB, was revealed by JTA-1 and JTA-2. They inhibited the enzyme by 23% and 25% respectively, thus approaching the selegiline activity, which was 42%. The possible mechanisms of neuroprotection of JTA-1 and JTA-2 might be a result from the inhibition of hMAOB, which catalyze the production of neurotoxic p-quinone from 6-OHDA

Simultaneous quantification of the major flavonoids from wild spinach by UHPLC-HRMS and their neuroprotective effects in a model of H2O2-induced oxidative stress on SH-SY5Y cells

A modified UHPLC-HRMS method for simultaneous quantification of eight flavonoids from the aerial parts of the wild spinach (Chenopodium bonus-henricus L.) was re-validated for specificity, the limit of detection and quantitation limit, linearity, accuracy, and precision. The glycosides of spinacetin (Chbhnf-04, Chbhnf-06, and Chbhnf-08) and patuletin (Chbhnf-01) were the predominant compounds. The total amount of assayed flavonoids from the aerial parts of a title plant was estimated to be 1.82% and 1.4% in two different populations from Vitosha Mountain (Bulgaria). The neuroprotective properties of compounds Chbhnf-02, Chbhnf-04, Chbhnf-06, Chbhnf-07, Chbhnf-08 were further assessed using a model of H2O2-induced oxidative stress on human neuroblastoma SH-SY5Y cells. All tested flavonoids demonstrated statistically significant neuroprotective activity close to that of silibinin. Patuletin (Chbhnf-07) and spinacetin (Chbhnf-08) triglycosides showed the most protective effects at the lowest concentration of 50 µM

Doxorubicin and Quercetin Double Loading in Modified MCM-41 Lowered Cardiotoxicity in H9c2 Cardioblast Cells In Vitro

Background: One of the therapeutic limitations of the use of doxorubicin (DOX) as an anticancer drug is its cardiotoxicity. Its hydrophilicity also causes difficulties in achieving sustained release. The simultaneous delivery with the well-known natural antioxidant quercetin could ameliorate its cardiotoxicity. Thus, the main aim of this work is to study the potential of carboxylated and non-carboxylated mesoporous silica MCM-41 nanoparticles for double loading of the hydrophilic doxorubicin hydrochloride and hydrophobic quercetin (Q) in one nanocarrier with a modified release pattern to reduce the cardiotoxic side effects of doxorubicin in vitro. Methods: The methods included the modification of MCM-41, single and double loading of modified and non-modified MCM-41, physicochemical characterization, in vitro release tests and kinetic study, and in vitro cell viability studies. Results: Doxorubicin and quercetin were successfully double-loaded with encapsulation efficiency (EE) of 43 ± 4.1% and 37 ± 4.5%, respectively, in native MCM-41. The post-synthetic carboxylation led to 49 ± 4.3% EE (DOX) and 36 ± 4.0% (Q) and double lowering of the cardiotoxicity on H9c2 (IC50 = 5.96 µm). Sustained release profiles over 72 h were achieved. Conclusions: A successful procedure was proposed for the efficient double loading of a hydrophilic drug and a hydrophobic drug. The carboxy-modified double-loaded nanosystems demonstrate a decreased in vitro cardiotoxicity of doxorubicin and can be considered as a potential chemotherapeutic formulation

Improvement of in vitro antioxidant activity of kaempferol by encapsulation in copolymer micelles

Antioxidant capacity of poorly soluble natural antioxidant kaempferol, in particular free or loaded in two types of cationic micelles, was studied on non-enzyme induced lipid peroxidation (LPO) in vitro. The micelles were based on triblock copolymers - poly(2-(dimethylamino)ethyl methacrylate-b-poly(propylene oxide)-b-poly(2-(dimethylamino)ethyl methacrylate (PDMAEMA-PPO-PDMAEMA) and poly(2-(dimethylamino)ethyl methacrylate-b-poly(ε-caprolactone)-b-poly(2-(dimethylamino)ethyl methacrylate (PDMAEMA-PCL-PDMAEMA). The lipid peroxidation was induced by incubating of rat liver microsomes with iron sulphate and ascorbic acid (Fe2+/AA). The effect of free and micellar kaempferol (at concentrations 25, 50 and 75 μg/ml) was assessed after 20 min incubation time. In the non-enzyme lipid peroxidation model, the kaempferol-loaded micelles significantly decreased the formation of malondialdehyde (MDA). The effect of kaempferol loaded in PDMAEMA-PCL-PDMAEMA micelles was more pronounced, showing an improved antioxidant activity in the conditions of oxidative stress and lipid peroxidation in vitro

Vibrational Characterization and Antioxidant Activity of Newly Synthesized Gallium(III) Complex

The gallium(III) complex of orotic acid (HOA) was synthesized and its structure was determined by means of analytical and spectral analyses. Detailed vibrational analysis of HOA, sodium salt of HOA (NaOA) and Ga(III)-OA systems based on both the calculated and experimental spectra confi rmed the suggested metal-ligand binding mode. Signifi cant differences in the IR and Raman spectra of the complex were observed as compared to the spectra of the ligand and confi rmed the suggested metal-ligand binding mode. The calculated vibrational wavenumbers including IR and Raman scattering activities for the ligand and its Ga(III) complex were in good agreement with the experimental data. The vibrational analysis performed for the studied species, orotic acid, sodium salt of orotic acid and its Ga(III) complex, helped to explain the vibrational behaviour of the ligand vibrational modes, sensitive to interaction with Ga(III). The compounds HOA, NaOA and GaOA were investigated for possible antioxidant activity in a model of non-enzyme-induced lipid peroxidation on isolated rat microsomes. On isolated rat microsomes, administered alone, the compounds didn’t revealed pro-oxidant effects. In conditions of non-enzymeinduced lipid peroxidation, only the complex GaOA showed antioxidant activity. HOA and NaOA didn’t reveal antioxidant activity. We suggest that the antioxidant activity of the complex GaOA, might be due to the presence of gallium in the structure of GaOA.</p

In vitro effects and in silico analysis of newly synthetized pyrrole derivatives on the activity of different isoforms of Cytochrome P450: CYP1A2, CYP2D6 and CYP3A4

Four pyrrole based hydazide-hydrazones with established low hepatotoxicity and promising antiproliferative activity were evaluated (at 1µM concentration) for possible inhibitory activity on human isoforms of Cytochrome P450 CYP1A2, CYP3A4 and CYP2D6. The compounds didn’t exert any statistically significant inhibitory effects on CYP1A2 and CYP2D6. However on CYP3A4 only 12 resulted in low statistically significant inhibitory effect decreasing the enzyme activity by 20%, compared to the control (pure CYP3A4). In addition the potential interactions of 12 and the evaluated CYP isoforms were displayed after molecular docking with Glide (Schrödinger). Induced-fit simulations and binding free energy (MM/GBSA) calculations were applied to elucidate the accessibility in each CYP isoform. The most active CYP3A4 inhibitor 12 demonstrated good binding affinity and was in close vicinity to the het Fe ion (2.88 Å). Overall, good correlation between the in vitro results and the free binding MM/GBSA recalculations were observed

In vitro protective effects of encapsulated quercetin in neuronal models of oxidative stress injury

The aim of the present study was to evaluate the protective effects of free and encapsulated quercetin against oxidative stress injury in neuronal SH-SY5Y cells and isolated rat brain synaptosomes. Quercetin (QR) was encapsulated in nanoparticles consisting of sodium alginate and chitosan and the ratio between both biopolymers was 10:1 or 1:10, respectively. The nanoparticles formulated with higher amount of sodium alginate were negatively charged, whereas those with higher chitosan amount were positively charged. The protective effects of free and encapsulated quercetin were studied in two in vitro models: H2O2-induced oxidative stress in human neuroblastoma SH-SY5Y cells and 6-hydroxydopamine (6-OHDA) induced neurotoxicity in isolated rat brain synaptosomes. Comparing to free quercetin, quercetin encapsulated in the nanoparticles formulated with higher chitosan concentration exerted more pronounced neuroprotective activity in a model of H2O2-induced (1 mmol/L H2O2, 15 min) oxidative stress in neuroblastoma SH-SY5Y cells. A similar trend was observed in a model of 6-OHDA induced neurotoxicity in rat brain synaptosomes. In conclusion, encapsulation of quercetin in nanoparticles based predominantly on chitosan improved its neuroprotective activity in vitro